4(b), and 4(c) illustrate the measured field patterns at the center frequency of the simple, L-feed, and T-feed excited elliptical DRAs, respectively.
The radiation and reflection characteristics of the elliptical DRA energized with various geometries of microstrip-line feed are summarized in Table 1. From the experimental observations, it is found that the elliptical DRA with simple microstrip feed offers moderate gain and bandwidth. It is also noted that L-feed excitation offers high gain and high bandwidth. The bandwidth is found to be larger for T-feed excitation, but the gain is poor. Independent of the geometry of the microstrip feed line employed here, the gain and bandwidth of the elliptical DRA is reasonably high, as compared with that of conventional patch antennas.
4. CONCLUSION
In this paper, an elliptical dielectric resonator antenna (DRA) energized with microstrip feed lines of different geometries has been investigated. The experimental results show that the resonant frequency as well as the operating bandwidth increases with an increase in the branching of the strip line feed. The good radiation performance, wide bandwidth, and exceptionally high gain make the proposed elliptical DRA a more suitable candidate for mobile communication and Bluetooth applications.